Somatic DNA Alterations of the 81 Locus of Oxytricha trifallax: Mechanisms and Evolution of its Alternative Processing

9600663 Herrick一项跨纤毛虫谱系的系统发育调查将监测Oxytricha fallax的81个位点的加工的起源和分子进化。81基因座是特别感兴趣的，因为它已被证明，在体细胞大核的发育过程中，它被加工形成三个重叠的大核染色体。系统发育调查将与简并引物PCR的大核间隔的替代处理的DNA中的关系越来越远的纤毛虫的代表。将对扩增的DNA进行测序和分析，以获得分子和相关见解，并确定进一步简并PCR引物的设计，以允许检测更远的相关序列。 %纤毛虫以程序化的方式通过消除特定的DNA序列来加工其生殖细胞核以产生体细胞核。一个特殊的基因座，尖毛藻的81基因座，已经显示出是不寻常的，因为它被交替加工以产生三个重叠片段，总共有三个开放阅读框。本研究将利用该区域比较相关的纤毛原生动物的DNA中的相关序列，希望了解程序化基因重排的进化。这种程序化的DNA重排在哺乳动物肿瘤发生期间的免疫细胞基因重排和随机重排中观察到，并且对这些简单原生动物中的过程的进化的洞察可以为理解更复杂生物体中的过程提供基础。 ***

9600663 Herrick A phylogenetic survey across a spectrum of ciliates will monitor the genesis and molecular evolution of the processing of the 81 locus of Oxytricha fallax. The 81 locus is of particular interest because it has been shown that during the development of the somatic macronucleus it is processed to form three overlapping macronuclear chromosomes. The phylogenetic survey will be done with degenerate-primer PCR of macronuclear intervals representative of alternative processing in the DNAs of ever more distantly related ciliates. The amplified DNAs will be sequenced and analyzed for molecular and relational insights as well as determining the design of further degenerate PCR primers to permit detection of more distantly related sequences. %%% Ciliates process their germline nucleus to produce a somatic nucleus by eliminating specific DNA sequences in a programmed fashion. One particular locus, the 81 locus of Oxytricha falfax, has been shown to be unusual in that it is alternatively processed to produce three overlapping fragments with a total of three open reading frames. This study will use this region for a comparison of the involved sequence in DNA from related hypotrichous ciliated protozoa in the hope of understanding the evolution of programmed gene rearrangements. Such programmed DNA rearrangements are observed in immune-cell gene rearrangements and stochastic rearrangements during tumorigenesis in mammals and insight into the evolution of the process in these simple protozoa can provide a basis of understanding of the process in more complex organisms. ***